Within recent years, the oil and gas industry has developed the use of hydraulic fracturing to produce what was once considered nonproductive oil and gas formations. This hydraulic fracturing technology may require the use of high volumes of water to be pumped into subterranean wells under tremendous rates and pressures to pry rock apart, thereby allowing the oil and gas that is trapped within the matrix of the oil and gas formations to migrate to the wellbore and production casing. Although the use of this technology may have allowed high volumes of oil and gas recovery from the oil and gas formations, the use of these large volumes of water has been widely scrutinized. Because the water that may be used during these fracturing operations is preferably clean and free from contaminants, current technologies may use fresh water sources that may normally be used for irrigation and human consumption. The use of these fresh water supplies may have an impact on the availability of fresh water for human consumption and irrigation.
Although the water that may be pumped into the oil and gas formations may be recovered over the production life of the oil and gas well, the water may become contaminated with chemicals from the fracturing process and minerals that are leached from the producing reservoir during the production of the well. Many oil and gas reservoirs may have been created from decomposed organic matter generated from oceanic sea beds. Fresh water may mix with the salt water that may typically be produced from the hydrocarbon formations making both the frac water and the formation water unsuitable for human consumption or reuse for hydraulic fracturing. This water that may be produced or that flows back from the well may then be disposed of by pumping it into deep nonproductive oil and gas formations. This cycle may be repeated for each well and may use hundreds of thousands of barrels for each operation.
Recently this disposal process has come under scrutiny due to increased seismic activity that has occurred in conjunction with the pumping of the water into these subterranean reservoirs. It is for this reason that the industry has an increased need to find a way to reduce the amount of water that may be disposed of in these underground formations. The volume of water and the high level of the Total Dissolved Solids (“TDS”) may make it difficult to filter using a Reverse Osmosis unit for surface discharge purposes. In the past, distillation systems may have been used to evaporate and condense the water for discharge purposes. However, the cost for the energy or BTUs to distill the water proved to often be uneconomical to use on a large scale basis.
In another instance, evaporation processes may have been used to eliminate the water and recover the solids contained in the water. These systems may spray large volumes of water into the air using blowers and misting systems to evaporate the water. The solids may then fall into collection or evaporation pits. This process may be problematic due to wind causing the solids or salt to be blown outside of the evaporation pits or collection areas. This may then be compensated by the use of wind walls to prevent the drifting of the sprayed/misted water. These wind walls may generate static areas of high humidity air masses, thereby reducing the efficiencies of the evaporation process. In the past, this may have been compensated for by setting up wind sensors that would turn blowers on and off on different sides of the evaporation pits to compensate for wind direction.
In another instance, an enclosure may be placed over the entire evaporation pit to prevent drift caused by the wind. In this case, the enclosure may be ventilated to continuously move air into and out of the enclosure to avoid saturation of the air mass.
Therefore, there may exist a need for a system to evaporate and/or reduce the volumes of water that are being disposed of without the issues of containment that are generated by blowing high solids water into the atmosphere, and allowing them to fall into collection or evaporation pits.